Coal stoker



N. S. MILLER Jan. 10, 1939.

GOAL STOKER Filed April 21, 1937 wwm.

Patented Jan. 10, 1939 UNITED STATES PATENT OFFICE 6 Claims.

My invention relates to coal stokers, and more particularly to air supply means for the retorts therein, and my main object is to provide a tuyere for this purpose which attains high efflciency by increasing the diffusion of air to the fuel being consumed and thus promoting the thorough combustion thereof.

A further object of the invention is to provide a tuyere for the stoker whichis self-cooling along the zones of combustion by means of water circulation.

A still further object of the invention is to design the novel tuyre as an annular cap or mounting between the retort and the wall of the air chamber in the stoker assembly.

Another object of the invention is to design the novel tuyere in a manner to join and firmly secure a sectional retort in the air chamber of the stoker.

An additional object of the invention is to construct the tuyere in the form of a unit which is readily applicable to or removable from the stoker without dismantling any part thereof.

An important object of the invention is to design tuyere along lines of simplicity and economical manufacture.

With the above objects in viewrand any others which may suggest themselves from the description to follow, a better understanding of the invention may be had by reference to the accompanying drawing, in which Fig. l is a vertical section through a stoker fire-pot installation, partly in elevation, showing the novel tuyere installed;

Fig. 2 is a perspective view of the tuyre; and

Fig. 3 is a detailed section onthe line 3-3 of Fig. 1.

In the design of stokers for furnaces, boilers, etc., it is essential to provide means for securing as thorough a combustion of the fuel as possible, such means usually including a tuyere marginally of the fire-pot or retort for the supply of air under pressure. While considerable emciency has been obtained in various forms of stokers, a

, detrimental factor is the rapid disintegration and destruction of the tuyre from the high temperature in the combustion zone. I am aware that water cooling has been devised for the protection of the tuyere from excessive heat, but such designs as have come to my attention occasion other involvements and deficiencies which I have endeavored to eliminate from the structure constituting my invention.

In accordance with the foregoing, specific reference to the drawing indicates the fuel supply duct of the stoker under consideration at H], the same developing into the funnel-shaped retort II. It is noted that the latter is in a series of laterally-assembled sections, these having tongues Ha at the bottom which seat in a channel Illa of the fuel duct in order to support the retort thereon. The sections of retort II are of identical form, so as to be interchangeable or replaceable in case any become defective or break by unequal expansion or contraction from changes in temperature. The air chamber wall is indicated at I2, and it is seen that the upper portions of the retort sections are formed with vertical fins llb which extend to the said wall to form spacers and provide room between the air chamber wall and the retort for the cooling of its sections. The latter are also formed with horizontal slots He by means of which air from the chamber l2 may enter the retort to promote the combustion of gases therein.

The novel tuyere comprises an annular chamber l3 whose inner wall is extended downwardly as indicated at I3a to rest on the upper edge of the retort I I. The extension is cut along its bottom edge with a series of arch-shaped notches l3b. The outer wall of the tuyere is also ex- "tended downwardly with a skirt section l3c-in the upper part of which is a circular series of perforations l3d. As seen in Fig. 1, the air chamber wall I2 is embedded in the firebrick M of the stoker foundation, and the skirt I30 of the tuyere extends through the fireclay floor l5 of the general combustion chamber IE to also become embedded in the firebrick; The tuyere chamber is intended to be cooled by the circulation of water or any other suitable cooling agent entering through a pipe ll into a nipple l8 communicating with the bottom of the chamber. The liquid is diverted sidewise by a partition He in the tuyere to travel around and return to a point on the other side of the partition for egress by way of a nipple l9 and a discharge pipe similar to the entrance pipe H. The nipples I8 and I9 are welded to the bottom of the tuyere, and the approach to their bottom portions is by way of an opening Ila. in the air chamber I2. Thus, it is possible to remove the fittings leading to the nipples and enable the tuyere to be lifted from the' retort and combustion chamber in case the removal or replacement of the tuyre is considered necessary.

In order that the tuyere may be securely attached to the retort H, the'latter is formed with a number of side pins Hd at intervals to cooperate with si'milarly-positioned bayonet-slots I if out in the tuyere skirt I30. Thus, fastening of the tuyere not only holds it firmly down on the retort, but also serves to secure the retort sections more firmly in the assembled position. Finally, the retort and air chamber wall are formed at the top with raised and tapered rims He and Ho respectively in order to prevent ashes escaping through the notches l3b and openings lid from falling into the air chamber I2, the tapers of the rims serving to shed or return such ashes as tend to accumulate thereon.

It is evident from the above description that the novel tuyere is situated at a point where the cooling factor affects its vital elements. Thus, one of these is the inner wall extension I3a. by way of whose notches the air from the chamber l2 issues in jets to vitalize the combustion in the retort. With the comparatively large stock of the tuyere water chamber l2 constantly being cooled, it follows that cooling rapidly extends by conductlvity to the lesser stock in the extension l3a, so that, though the same may be in a zone of intense heat, it will efiiciently resist the same. This eflect also applies to the tuyere skirt I30 in the zone of the perforations l3d, where the air from the chamber l2 issues into the general combustion chamber in clifiused form to complete combustion in the bottom of the chamber contents. The tuyere will thus maintain its immediate extensions relatively cool and prevent the adhesion of clinkers thereto. It is also evident that the tuyere applies as an annular bridge over the space between the retort and air chamber wall, and forms a cap or mounting to complete these parts in a compact top. Yet, should a replacement be necessary in the retort or a defect develop in the tuyere as a result of excessive heat, changes of temperature, or other causes, it is a relatively simple matter to disconnect the water supply and discharge fittings from the tuyre.

and to give the latter a twist for release from the retaining pins Md. The tuyre may then be lifted out and the replacement readily made.

The novel installation is eficient not only from the viewpoint of service and replacement, but also from that of economy. The tuyere, on account of its unitary and compact form can be conveniently and cheaply cast, or made up of stampings welded together so that its installation or replacement is economical.

While I have described the novel tuyere along specific lines, various minor changes or refinements may be made in the same from time to aliases time as conditions or specifications may require, and I consider all such changes and refinements as coming within the scope and spirit of the invention as covered in the appended claims.

I claim:-

1. A tuyere for a retort situated spacedly within an opening in the firebox floor comprising: an annular conduit for a cooling agent, and a downward extension of the inner wall of the conduit resting on the top of the retort adjacent the inner edge thereof, the extension being periodically recessed from its lower edge to form a series of openings for admission of air from the space between the retort and the firebox floor directly to said retort top and inner edge thereof.

2. A tuyere for a retort situated spacedly within an opening in the firebox floor, the top of the retort being substantially even with the latter, comprising: an annular conduit for a cooling agent, and a downward extension of the outer wall of the conduit lining the edge of said opening, said extension being formed with a horizontal series of openings a short distance above said floor.

3. A tuyere for a retort situated spacedly within an opening in the firebox floor, the top of the retort being substantially even with the latter, comprising: an annular conduit for a cooling agent, a downward extension of the inner wall of the conduit resting on top of the retort adjacent to the inner edge thereof, the extension being periodically recessed from its lower edge to form a series of openings directly facing said retort top and inner edge thereof, and a downward extension of the outer wall of the conduit lining the edge of said floor opening, said extension being formed with a horizontal series of openings a short distance above said floor.

4. Til structure of claim 2, an air chamber wall alo g the inner side of the extension, and

means removably attaching the latter to said series of openings.

NICHOLAS S. 

